Lead poisoning is still a potential hazard today, especially for those children who are at risk due to environmental exposure. In the October 2005 issue of "Pediatrics," the American Academy of Pediatrics' Committee on Environmental Health states that children whose families live in old buildings are exposed to deteriorating paint that contains lead. As a result, lead paint chips, plaster and/or dust will often wind up in their mouths. Most of the time, the children will not have any symptoms of lead poisoning and their abnormal levels will only be picked up during routine exams. This is why it is recommended for all children who are at risk to have finger stick samples taken of their blood lead levels.
What is DMSA?
DMSA is used to treat children who are suffering from lead poisoning. Its chemical name is 2,3-dimercaptosuccinic acid. DMSA works by forming two bonds with the lead ion, and in so doing, stops lead from being able to bind to the protein within the child's tissues. The resultant compound can then be excreted through the child's kidneys, with the maximum urinary excretion occurring within two to four hours.
Recommendations
Blood lead levels that are higher than 10 micrograms/dL are considered to be abnormal. It is recommended, therefore, that children with levels that are from 15 to 19 micrograms/dL be checked every three months. Meanwhile, the source of the lead poisoning must be identified and eliminated, and the parents must be educated as well. For levels that are higher than 20 micrograms/dL, the level should be confirmed by taking a blood sample from the child's veins. It is still not necessary to treat with DMSA, but it is vital for the source to be eliminated and the parents educated. If the blood lead levels are higher than 45 micrograms/dL, and this level has been confirmed by a venous blood sample, it is now time for DMSA chelation.
Before Starting Treatment
The Centers for Disease Control and Prevention (CDC) advises pediatricians to first consult with an expert in chelation therapy. They can call a Poison Control Center or the CDC for contact information. Before receiving DMSA, the child must have blood tests, serum tests of their liver and neurological tests. Any signs of the lead levels affecting the child's brain must be considered life-threatening. The brain being affected in this way is referred to as encephalopathy, and the child would have continual vomiting, a severe headache and be very drowsy. That child must be admitted to the hospital and receive additional treatment, as well as DMSA chelation.
Chelation Procedures
The child will then receive DMSA at 10 mg/kg/dose every 8 hours for 5 days. On the sixth day, the child should start to receive 10 mg/kg/dose every 12 hours for 14 days. The maximum amount of DMSA that should be given is 500 mg/dose. While receiving this treatment, the child's blood lead levels and platelet levels must be monitored. The lead levels should drastically decrease by the end of the first week of treatment. Many times, however, the blood lead levels will return to as much as 75 percent of the pretreatment level. It is, therefore, important to recheck the child's lead level 7 to 21 days after the treatment has been finished. Serum liver tests and neurological tests should also be done. If another round of DMSA treatment is needed, it is best to have two weeks where no treatment is given, before starting it again.
References
- CDC: Managing Elevated Blood Lead Levels Among Young Children. Recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention
- "Katzung & Trevor's Pharmacology"; Anthony Trevor, PhD, Bertram Katzung, M.D., PhD, Susan Masters, PhD; 2002
- "Pediatrics"; Lead Exposure in Children: Prevention, Detection, and Management; Committee on Environmental Health; October 2005
